We have continued to evaluate polyamines in extracellular fluids (blood and urine) as markers of pathology; i.e., spermidine prescribes cell loss fraction of the body and putrescine the percentage of cells in the proliferative fraction. To facilitate polyamine evaluation in cancer patients and to assess tumor cell kinetic parameters, we are developing a simple, rapid and accurate assay for polyamines. Ornithine decarboxylase (ODC) regulation in normal and neoplastic cells has been studied. ODC is expressed in Rat-1 cells as a discrete event of G1. In Rat-1 cells transformed by Rous sarcoma virus, the extent of induction increases and it remains elevated during S phase, presumably conferring a growth advantage to transformed cells. ODC has been purified to homogeneity from rat and calf liver and is being characterized. The enzyme retains the ability to initiate RNA polymerase I and increase the amount of 45S RNA detectable in rat liver nuclear preparations. We are now testing the effect in isolated nucleolar preparations since all the RNA polymerase I is present in nucleoli. Studies are in progress to ascertain what properties of the protein are involved in catalytic activity as opposed to initiation activity.